1 fan beam DI piezo "aimed straight down" to provide dedicated all-inclusive DI echoes...(to render into a non-directional DI image) ...
2 fan beam SI piezoes "aimed 30° from horizontal" to provide separate left and right SI echoes ...(to render into a directional left and right SI image) ...
http://i477.photobucket.com/albums/r...psj8hgchko.png
Rickie

